OFFSET
0,2
COMMENTS
Number of integer pairs (x,y) satisfying x^4+y^4 <= n, any -n <= x,y <=n.
EXAMPLE
a(6) = 9 counts (x,y) = (-1,-1), (-1,0), (-1,1), (0,-1), (0,0), (0,1), (1,-1), (1,0) and (1,1).
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Apr 24 2010
STATUS
approved